In accordance with recent developments in the electronic communication industry, user equipment such as a mobile terminal, electronic scheduler, personal complex terminal, laptop computer, and wearable device have become necessities in modern society and important means for transferring rapidly changing information. Such user equipment includes a photographing function and an image editing function in a basic specification, and it is difficult to find user equipment that has no photographing function.
Various technologies are applied to user equipment produced recently so that a user can focus on a desired location quickly. In particular, user equipment using a contrast focusing method can provide the user with a correctly focused image by calculating a correct contrast value from an input image.